JPH11258142A - Apparatus for measuring distribution of contaminated particle in working oil of press machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an apparatus for measuring a distribution of contaminated particles in a working oil which measures a particle size with the utilization of light transmission holes of different sizes of a plurality of measurement units and widens a measurable range of the particle size. SOLUTION: A plurality of measurement units 12 are set at a working oil path 11 of a press machine. Each measurement unit 12 is constituted of a measurement cell 21 having a measurement path 22 communicating with the working oil path 11, a pair of emission and reception rod-shaped light-transmitting bodies 24, 25 penetrating a peripheral wall of the measurement path 22 from inside to outside and arranged to confront each other via a measurement gap between inner end faces, a light-emitting device 26 disposed at an outer end of the emission light-transmitting body 24, a photodetector 27 disposed at an outer end of the reception light-transmitting body 25 and a photomask 28 interposed between the outer end of the reception light-transmitting body 25 and the photodetector 27 and having a light transmission hole. Sizes of the light transmission holes of photomasks 28 of all measurement units 12 are changed stepwise so that the light transmission hole of the photomask 28 of each measurement unit 12 is adaptable in size to a specific range only among an entire range of measurement particle sizes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring, for each size, contaminant particles contained in lubricating oil for monitoring the state of contamination of hydraulic oil of a press machine, for example, lubricating oil.

[0002]

2. Description of the Related Art The applicant has previously disclosed that a measuring unit is provided in a hydraulic oil passage of a press machine, and the measuring unit penetrates a peripheral wall of the measuring passage inside and outside, and a measuring gap is formed between inner end faces. And a pair of light-emitting and light-receiving rod-shaped light transmitters arranged so as to be opposed to each other, and a light-emitting device disposed at an outer end of the light-emitting light transmitter and an outer end of the light-receiving light transmitter And a photomask interposed between the outer end of the light receiving side light transmitter and the light receiver and having a light passage hole.
No. 81696).

[0003]

In the above apparatus, the size of the light passage hole is set according to the size of the measured particle diameter.

Usually, the ratio between the maximum particle size and the minimum particle size to be measured is about 10 times. Since the amount of light that blocks light passing through the light passage hole is blocked by the particles is proportional to the square of the particle diameter, the measurement accuracy is low for particles that are very small relative to the size of the light passage hole. Therefore, there is a problem that the range of measurable particle diameter is narrow in the measurement by one measuring unit.

An object of the present invention is to provide an apparatus for measuring the distribution of contaminant particles in hydraulic oil of a press machine capable of measuring a wide range of particle diameters.

[0006]

According to the present invention, there is provided an apparatus for measuring the distribution of contaminated particles in hydraulic oil of a press machine according to the present invention, wherein a plurality of measurement units are provided in a hydraulic oil passage of the press machine, and each measurement unit communicates with the hydraulic oil passage. A measurement cell having a measurement passage, and a pair of light-emitting and light-receiving side rod-shaped light transmitters that penetrate the inside and outside of the peripheral wall of the measurement passage, and are arranged to face each other with a measurement gap between the inner end faces. A light-emitting device disposed at the outer end of the light-emitting side light transmitter and a light receiver disposed at the outer end of the light-receiving side light transmitter, and interposed between the outer end of the light-receiving side light transmitter and the light receiver. And a photomask having a light-passing hole, and the size of the light-passing hole of the photomask of each measurement unit is adjusted so that the size of the light-passing hole can be adapted only to a specific range in the entire range of the measured particle diameter. Photo of measuring unit The size of the transparent holes in disk is one that has been gradually changed.

In the apparatus for measuring the distribution of contaminated particles in hydraulic oil of a press machine according to the present invention, the particle diameter is measured by using light passing holes of different sizes of a plurality of measuring units.
The measurable particle size range can be wide.

Further, in the above device, the light receiver outputs a signal corresponding to the amount of light received through the light passage hole, which is blocked by the particles passing through the measurement gap, and the output signals of the light receivers of all the measurement units are output. The signal processing means is input to the signal processing means, and for each measurement unit, the input output signal is converted into a unit measurement flow rate obtained based on the measurement gap, the flow rate of the hydraulic oil passing therethrough and the size of the light passage hole. Convert to the corresponding data, extract the converted data, only the portion corresponding to the specific range from the entire range of the particle size to be measured, the extracted data can correspond to the entire range of the particle size to be measured It is preferable to perform the joining process as described above.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

Referring to FIG. 1, in a hydraulic oil passage 11 of a press machine, three measuring units 12 forming three channels are provided at predetermined intervals in a length direction of the hydraulic oil passage. The output signal of the measurement unit 12 is input to the signal processing system 13. The output signal of the signal processing system 13 is input to the analysis / storage / display 14. The basic structure of the three measurement units 12 is the same.

As shown in detail in FIG.
12 has a measurement cell 21. The measurement cell 21 is formed in a rectangular parallelepiped block shape with aluminum,
It has a straight measuring channel 22. The measurement passage 22 is
A circular cross-sectional area having a diameter of 8 mm,
It is a size that allows up to 3 l / min of hydraulic oil to pass with a margin.

A pair of through holes 23 are coaxially formed on the peripheral wall of the measurement passage 22 on a line perpendicular to the axis center of the measurement passage 22, and a pair of rod-shaped light emitting side lights are formed in these through holes 23. The transmitting body 24 and the light receiving side light transmitting body 25 are inserted. The light emitter 26 is arranged so that its light emitting surface is opposed to the outer end face of the light emitting side light transmitting body 24, and the light receiver 27 is arranged such that its light receiving surface is opposed to the light receiving side light transmitting body 25. ing.

Each of the light transmitting members 24 and 25 is formed of a cylindrical rod lens (Nippon Sheet Glass selfoc lens). A measurement gap C of about 1 mm exists between the inner ends of the two light transmitting bodies 24 and 25. A disc-shaped photomask 28 is interposed between the light transmitting body 25 on the light receiving side and the light receiver 27.

A protective tube is provided around both light transmitting bodies 24 and 25.
31 and 32 are arranged, and the light emitting device 26 and the light receiving device 27
Are housed in holders 33 and 34, respectively, whereby the cell 21, the light transmitters 24 and 25, the light emitter 26, the light receiver 27, and the photomask 28 are integrated.

The rod lens uses a glass rod having a diameter of about 1 to 2 mm as a lens medium and functions as a lens by a square refractive index distribution in the rod. As shown in FIG. 4 for length P
There are different sizes, and each of the four sizes shows unique optical characteristics. That is, the 1P (pitch) rod lens 41 shown in FIG. 3A forms an erect image of the object on the incident end face as it is on the output end face, and the 3 / 4P rod lens shown in FIG.
42 forms an erect image of an object at infinity on the exit end face, and FIG.
The 1 / 2P rod lens 43 shown in FIG. 3 forms an inverted image of an object on the incident end face on the output end face, and the 1 / 4P rod lens 44 shown in FIG. 3D forms an inverted image of an object at infinity on the output end face. Image.

A 1 / 4P rod lens is used for the light-emitting device-side light transmitting body 24, and a 1/2
A rod lens of P is used.

The light emitter 26 comprises a laser diode.
The light receiver 27 is composed of a photodiode.

The three measurement units 12 are provided with three types of photomasks 28. Three types of photomasks 28
Have the same outer shape but different sizes of light passage holes 28.
a, 28b and 28c are provided at the center. Three light passage holes
The shapes of 28a, 28b, 28c are all square,
Each side d1, d2, d3 is 50 μm, 100
μm and 200 μm. However, for example, 20 to 60 μ
When measuring m accurately, the size of the photomask varies depending on the particle diameter range to be measured, such as using a photomask of 60 μm and 150 μm.

The light emitted from the light emitter 26 traverses the measuring gap C as dispersed parallel rays and is received by the light receiver 27. The light receiving area of the light is equal to the light passing holes 28a and 28a of the photomask 28.
b, 28c, and 28d.

FIG. 5 shows a state in which the measuring particles P sequentially block the light receiving surface in the order of (a) to (f), and the signal output from the light receiver 27 in response to this state is: This is shown in FIG. In the state where there is no measurement particle P, the light receiving surface receives 10 light.
0% received. When the light receiving surface is blocked by the particles P,
The output signal of the light receiver 27 fluctuates according to the blocked area.
One pulse is output for one particle. The height of the pulse is proportional to the blocked area, and the blocked area is
It is proportional to the square of the particle size.

The signals output from the three measurement units 12 are processed by the signal processing system 13 for each measurement unit 12.

FIG. 7 is a block diagram showing an electric circuit for processing an output signal of each measurement unit 12. As shown in FIG.

A monitor signal corresponding to the generated light is output from the light emitting device 26. The monitor signal is passed through a sample-and-hold circuit 51 and an AD converter 52, and thereafter, is monitored by a CPU 57 for watching a change in light amount. Sent to

The light receiver 27 outputs a pulse signal as shown in FIG. 8A, which is sent to a low-pass filter 53 and a high-pass filter 54.

In the low-pass filter 53, the pulse component is removed, replaced with a level signal, passed through the AD converter 52, and sent to the CPU 57. The CPU 57 constantly compares the level signal with the monitor signal. When the level signal decreases, it is determined that the light transmitters 24 and 25 have become dirty or deteriorated, and the light transmitters 24 and 25 are replaced and inspected.

The high-pass filter 54 removes the DC component and replaces it with a pulse rising from zero, which is set to the ground level when receiving 100% light. The output signal of the high-pass filter 54 is shown in FIG. The signal that has passed through the high-pass filter 54 is sent to a comparator 55 and a peak detector 56. Comparator 55
The pulse generation confirmation signal shown in FIG. 8C is output. The peak detector 56 outputs a peak hold signal for AD conversion. FIG. 9 shows the relationship between the input signal and the output signal of the peak detector 56. The output signal of the comparator 55 is sent to the CPU 57 as it is, and the peak detector 56
Is sent to the CPU 57 after passing through the AD converter 52. The CPU counts the number of pulses for each pulse height. FIG. 10 is a flowchart showing a procedure for processing the output signal of the light receiver. When a pulse is generated (step 61), the peak is detected (step 62),
The peak is held (step 63). In this state, the A / D conversion is started (Step 64). When the A / D conversion is completed (Step 65), the CPU 57 reads the A / D conversion data (Step 66) and counts each data size (Step 67). Here, the presence or absence of a pulse is confirmed (step 68), and the peak is reset (step 68). From the start, this procedure is continuously performed until a certain time (a certain count) elapses (step 70), and the count result is transferred to the computer.

As shown in FIG. 11, the computer to which the count result has been transferred can be represented as a graph in which the horizontal axis represents the pulse height (particle diameter) and the vertical axis represents the pulse number (particle number). Data is stocked. FIG.
(a), (b) and (c) show three channels ch1 and ch2
, Ch3.

Here, considering the range of the particle size to be measured, in ch1, the range S in which a relatively small particle size is measured is considered.
1 and ch2, the range S2 in which a medium particle size is measured is measured with high accuracy, and ch3 the range S3 in which a relatively large particle size is measured with high accuracy. For example, in ch1, the light passage hole 28a of the photomask 28 is 50 × 50 μm
Therefore, particles having a size of 100 μm cannot be measured.
Has a size of 200 × 200 μm,
The measurement accuracy of particles is low.

The data shown in FIGS. 11A, 11B and 11C are actually measured values. 3 channels ch1, ch2
, Ch3, the light passage holes 28a, 28b, 2 of the photomask 28
Since the size of 8c is different, the flow rate of the measured fluid per unit time is different. For example, if the fluid velocity is constant, the photomask of ch3
In the case of 28, four times as many particles as the photomask 28 of ch1 were measured. Therefore, the data shown in FIGS. 11 (a), (b), and (c) cannot be directly subjected to comparison, and it is necessary to convert the data into data that can be compared under the same standard. is there.

The method of conversion will be described below. The calculation for the conversion is performed by software on-line by a computer.

Assuming that the cross section in the flow direction of the fluid as viewed through the light passage hole of the photomask is referred to as a measurement region, the area L of the measurement region is obtained by the following equation.

L = d · C where d is the length of one side of the light passage hole of the photomask perpendicular to the fluid flow direction, and C is the measurement gap.

Next, assuming that the measured flow rate that has passed through the measurement area within the measurement time is Q, it can be obtained as Q = L · V · T. Here, V is the flow velocity of the fluid passing through the measurement area L, and T is the measurement time.

Assuming that the measurement reference flow rate is q, the conversion coefficient k
Is obtained by the following equation.

K = q / Q Therefore, when the measured value n is multiplied by the conversion ratio k, the converted value N is converted into data which can be compared with the measured value under the same standard.
Is required. That is, N = kn.

The data converted as described above is shown in FIG.
, (B) and (c). FIG. 12 (a), (b), (c)
Are shown as A,
B and C, which are superimposed on one graph, are as shown in FIG.

The curves A and B intersect at a point P1, and the curves B and C intersect at a point P2. Accordingly, the curve A uses a portion having a smaller particle diameter than the point P1, the curve B uses a portion between the points P1 and P2, and the curve C uses a point P2.
When a portion having a larger particle diameter is adopted, one continuous curve is obtained, which coincides with the actual particle distribution.

Next, an example of measuring the particle distribution will be described with reference to FIG.

In step 71, data such as the number of channels, the photomask size d, the measurement gap C, the measurement time T, the flow velocity V, and the measurement reference flow rate q are input. The number of channels is
3 is assumed. The three channels are ch1, ch2, ch
3 The difference code corresponds to channels 1, 2, and 3. The lengths d1, d2, d3 of one side of the light passage hole of the photomask of the three channels are 50, 100, 2 respectively.
00 μm. Measurement gap C is 1 mm, flow velocity V is 200 m
m / sec and the measurement time T is set to 50 sec. The measurement reference flow rate q is 100 ml, that is, 100,000 mm 3.

In step 72, the measured flow rate Q and the conversion coefficient k that have passed through the measurement area within the measurement time are determined.

First, based on L = d · C, the areas L 1, L 2, L 3 of the measurement areas of the three channels are obtained.

L1 = 0.05 × 1 = 0.05 mm 2 L 2 = 0.1 × 1 = 0.1 mm 2 L 3 = 0.2 × 1 = 0.2 mm 2 Then, since Q = L ・ V ・ T, 3 The measurement flow rate that has passed through the measurement area of one channel within the measurement time is determined.

Q 1 = 0.05 × 200 × 50 = 500 mm 3 Q 2 = 0.1 × 200 × 50 = 1000 mm 3 Q 3 = 0.2 × 200 × 50 = 2000 mm 3 Three channels based on the conversion coefficient k = q / Q The conversion coefficient of is obtained as follows.

K1 = 100000/50 = 200 k2 = 100000/100 = 100 k3 = 100000/200 = 50 The process proceeds to step 73 to start the measurement. In step 74, the measurement is performed for each channel. In step 74, the measurement results are compiled as data. Here, 10 to 150 μ
Assuming that the particles are distributed in the range of m, the measured values n1, n2, and n3 of the three channels are shown in Table 1 (in Table 1, 1).
The measurement data is shown at intervals of 0 to 25 μm, but actually there is measurement data at 1 μm intervals).

Then, the process proceeds to a step 75, wherein N = k ·
n, the conversion values N1, N2,
N3 is required. Table 2 shows the obtained converted values N1, N2 and N3.

[0046]

[Table 1]

[0047]

[Table 2]

In step 77, a specific particle size range is extracted according to the photomask size. In Table 2, ch
The number of particles of 1 and ch2 intersect at a particle diameter of 40 μm, and the number of particles of ch2 and ch3 is 90 μm
Crosses at Particle size 10 to 40 from ch1
μm data is extracted, and the particle size is 41 to 90 μm from ch2.
The data of m is extracted and the particle diameter of 91 to 150 μm is extracted from ch3.
Extract the data of m.

At step 78, the extracted data is
When arranged over the range of 50 μm, the results are as shown in Table 3, which is a particle size distribution N close to the actual distribution. In step 79, the obtained particle size distribution N is displayed. When the measurement is repeatedly performed, the process returns from step 80 to step 74.

[0050]

[0051]

[Table 3]

In the above, the number of channels is arbitrary. In addition, a plurality of measurement units may be installed at different locations in the hydraulic oil passage at different flow rates, or the measurement gap may be changed for each measurement unit.

As will be apparent from the above description, the feature of the present invention is that the size of the photomask can be easily changed according to the particle diameter to be measured, and furthermore, the size of the photomask can be adjusted within the range of the particle diameter to be measured. The point is that the number of channels can be changed at the same time.

[0054]

According to the present invention, since the particle size is measured by using the light passing holes of different sizes of the plurality of measurement units, the measurable particle size range can be widened. it can.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an apparatus according to the present invention.

FIG. 2 is a longitudinal sectional view of a measurement unit of the same device.

FIG. 3 is an explanatory diagram of a light transmitting body of the measurement unit.

FIG. 4 is an explanatory diagram of a photomask of the measurement unit.

FIG. 5 is an explanatory diagram showing a state in which a light receiving surface of a light receiver of the measurement unit is blocked by particles.

FIG. 6 is an explanatory diagram showing output signals of the light emitter corresponding to the state of FIG.

FIG. 7 is a block diagram showing an electric circuit for processing an output signal of the light receiver.

FIG. 8 is an explanatory diagram of output signals of devices constituting the block diagram of FIG. 7;

9 is an explanatory diagram of output signals of a device different from the device of FIG. 7 that constitutes the block diagram of FIG. 7;

FIG. 10 is a flowchart showing a procedure for processing an output signal of a light receiver.

FIG. 11 is an explanatory diagram showing measurement data after processing an output signal of a light receiver.

FIG. 12 is an explanatory diagram showing converted data after converting the data shown in FIG. 11;

FIG. 13 is an explanatory diagram showing an actual particle size distribution obtained by extracting required portions from the conversion data shown in FIG. 12 and joining them.

FIG. 14 is a flowchart showing a measurement procedure.

[Explanation of symbols]

 11 Hydraulic oil passage 12 Measuring unit 21 Measuring cell 22 Measuring passage 24 Light transmitter 25 Light transmitter 26 Light emitter 27 Receiver 28 Photomask 28a Light passage hole 28b Light passage hole 28c Light passage hole C Measurement gap

Claims (2)

[Claims] 1. A plurality of measuring units 12 are provided in a hydraulic oil passage 11 of a press machine. Each measuring unit 12 has a measuring cell 21 having a measuring passage 22 communicating with the hydraulic oil passage 11, and a peripheral wall of the measuring passage 22. And a pair of light-emitting and light-receiving rod-shaped light transmitters 24 and 25 arranged so as to face each other with a measurement gap C between the inner end faces thereof,
Light emitter 26 and light receiving side light transmitter disposed at the outer end of the
A light receiver 27 arranged at the outer end of 25 and a light receiving side light transmitting body
And a photomask 28 having a light passage hole interposed between the outer end of the photodetector 27 and the light receiver 27.The size of the light passage hole of the photomask 28 of each measurement unit 12 is determined by measuring the size of the measured particle diameter. The operation of the press machine in which the sizes of the light passing holes 28a, 28b.28c of the photomasks 28 of all the measuring units 12 are changed stepwise so as to be adaptable only to a specific range of the entire range. Oil contamination particle distribution measuring device. 2. A light receiver 27 outputs a signal corresponding to the amount of light received through the light passing holes 28a, 28b.
The output signal of the 12 light receivers 27 is input to the signal processing means 13,
The signal processing means 13 converts, for each measurement unit, the input output signal into data corresponding to the unit measurement flow rate obtained based on the measurement gap, the flow rate of the hydraulic oil passing therethrough and the size of the light passage hole. Then, from the converted data, only a portion corresponding to a specific range is extracted from the entire range of the particle diameter to be measured, and the extracted data is joined so that it can correspond to the entire range of the particle size to be measured. The apparatus for measuring the distribution of contaminant particles in hydraulic oil of a press machine according to claim 1.